The present invention relates to a rotary compressor for use in refrigerators, air conditioners, heat pumps, etc., and is particularly intended to achieve improvement in its muffler.
Heretofore, in a commonly used muffler in such rotary compressors, the discharge muffler is formed by forming a concavity beneath the lower bearing and covering this cavity with a flat plate, as defined by R. L. Dills' U.S. Pat. No. 2,764,342 and J. E. Bannister's U.S. Pat. No. 4,088,428. With these mufflers of the two U.S. patents, vibration sounds are transmitted through the plate and emitted into the closed case, thus still producing loud noise. They were thus imperfect as mufflers. Furthermore, a rotary compressor of a structure in which the discharge chamber is formed by providing a cup shape discharge cover on one side of the bearing which receives an end of the crankshaft and, further, a cylindrical discharge muffler is provided on this discharge chamber is known. Through employment of such a structure, the shortcomings in the aforementioned two U.S. patents are eliminated for enhanced muffling effect.
However, as a result of the cylindrical discharge muffler being separately installed within the closed case, the volume of the closed case was increased and this interfered with overall miniaturization. Moreover, the tendency of chattering coming out from the junction between the cylindrical discharge muffler and the discharge chamber remained unsuppressed.